Comment 7 for bug 1202201

Correction for the code that I pasted above that should be used.

            ToolbarButton {
                id: shareButton
                objectName: "shareButton"
                iconSource: "../../img/share.png"
                onTriggered: {
                    PopupUtils.open(sharePopoverComponent, shareButton);
                }
                text: i18n.tr("Share")
            }

So there is no 'caller' to be passed. Use the id of the button directly.